This invention relates to a laminated tape comprising a sheet with hook-fastening elements, especially of the self-gripping type, a molded article comprising a tape of this kind, and a process for manufacturing a molded article of this kind.
To secure a tape of this kind to a molded article such as a cushion made of cellular or foam plastic for a seat in a car, airplane, etc. during the molding operation, the tape is arranged on the inside of the mold, generally on the base, the face of the self-gripping sheet bearing self-gripping elements turned toward the inside wall of the mold. The foam is poured into the mold. The liquid foam comes into contact with the other face of the sheet. Once the foam is cured. the article is removed from the mold. The surface of the article then comprises self-gripping elements that allow covering fabrics or the like to be secured thereto. During the molding and securing operation, the self-gripping elements should be well protected from any contact with the liquid or pasty foam to prevent deterioration of their self-gripping power.
To protect these self-gripping elements, the art already includes the provision of a cavity formed by two ribs which project from the inside face of the mold and between which the tape is received. The latter is made of a material that is flexible enough to be inserted by force into the cavity and thus to create an impermeable space bounded by the ribs, the base of the mold, and the tape which is slightly bent and presses against the ribs. In theory, therefore, the self-gripping elements are protected from the infiltration of the liquid foam when it is poured into the mold. This method is time-consuming because the operator has to force the tape into the cavity each time. Secondly, it has been found in practice to be not very effective in preventing the penetration of the liquid foam into the impermeable space.
In order to improve the securing operation, thought was already given to gluing a metal strip to one of the faces of the sheet and to magnetizing the base of the cavity. The magnetizing effect thus keeps the tape properly oriented with its self-gripping elements on the side of the interior surface of the mold and it no longer turns, especially under the effect of the foam being poured. However, the liquid foam still tends to infiltrate through the interstices of the bond between the tape and the ribs which do not have a perfect seal. This type of product is disclosed in Applicant's French Patent No. 7804001, for example. Applicant's French Patent No. 7804001 also provides for replacing the metal strip with a layer of foam having the same function as the strip, that is, keeping the tape in place and preventing it from turning. The problem is not eliminated in either case, however.
An attempt was also made to overcome this difficulty by providing for the arrangement of a protective film on the self-gripping elements which are kept properly oriented toward the base of the cavity by means of the metal strip and are protected from the liquid foam by the protective film. However, this type of tape is not cost-effective in terms of production because the tapes are more expensive and take longer to manufacture. That is, protective films are added and have to be removed before fabric, for example, is secured to the article.